The present invention relates to a sputtering apparatus for forming a thin film on a thin-film device or the like by using a laser.
An example of a laser sputtering apparatus of this kind was disclosed in the Japanese Journal of Applied Physics in 1988 by Komura et al. and has an arrangement shown in FIG. 1. In this known laser sputtering apparatus, a target 16 and a substrate base 17 are provided in a vacuum tank 15 such that the substrate base 17 confronts the target 16. A substrate 18 is mounted on the substrate base 17. Meanwhile, a laser beam 19 of the second higher harmonic of visible light of a Q-switch YAG laser, which has a wavelength of 532 nm, is converged by an optical system 20 and is irradiated, through a vacuum sealing window 21 secured to the vacuum tank 15, onto the target 16 so as to deposit on the substrate 18, a thin film formed by material of the target 16.
However, in the known laser sputtering apparatus of the above described arrangement, the amount of processing of the target 16 varies with location of the target 16 due to distribution of intensity of the laser beam 19, thereby resulting in nonuniform thickness of the thin film deposited on the substrate 18. In order to make the thickness of the deposited thin film uniform, the substrate 18 may be moved in the vacuum tank 15 as in other sputtering apparatuses. However, in this case, the mechanism becomes quite complicated and it is difficult to cope with the change in thickness of the deposited thin film over time.
Meanwhile, particles forming the thin film deposited on the substrate 18 have different shapes due to a distribution of the intensity of the laser beam 19, thus making the structure of the thin film nonuniform.